:root{--ink:#101116;--muted:#626877;--line:#e5e8ef;--soft:#f6f7fb;--blue:#315cff;--violet:#7c3cff;--green:#159961;--white:#fff;--shadow:0 24px 70px rgba(27,38,75,.11)}
*{box-sizing:border-box}html{scroll-behavior:smooth}body{margin:0;color:var(--ink);background:#fff;font-family:"PingFang SC","Microsoft YaHei",system-ui,-apple-system,sans-serif;-webkit-font-smoothing:antialiased}a{color:inherit;text-decoration:none}.container{width:min(1140px,calc(100% - 48px));margin:auto}.nav-shell{position:sticky;z-index:20;top:0;height:72px;border-bottom:1px solid rgba(226,230,239,.85);background:rgba(255,255,255,.9);backdrop-filter:blur(18px)}.nav{display:flex;height:100%;align-items:center;gap:32px}.brand{display:flex;align-items:center;gap:10px;margin-right:18px;font-size:19px;font-weight:800}.brand-mark{display:grid;width:34px;height:34px;place-items:center;border-radius:10px;color:#fff;background:linear-gradient(145deg,var(--blue),var(--violet));font-size:12px}.nav-links{display:flex;align-items:center;gap:28px;color:#3b404b;font-size:14px}.nav-actions{display:flex;align-items:center;gap:12px;margin-left:auto}.button{display:inline-flex;min-height:44px;align-items:center;justify-content:center;padding:0 20px;border:1px solid transparent;border-radius:12px;font-size:14px;font-weight:700}.button-primary{color:#fff;background:linear-gradient(135deg,var(--blue),var(--violet));box-shadow:0 12px 28px rgba(76,73,240,.22)}.button-light{border-color:var(--line);background:#fff}.hero{padding:100px 0 84px;background:radial-gradient(circle at 82% 20%,rgba(81,81,255,.12),transparent 28%),linear-gradient(180deg,#fff,#fafbff)}.hero-grid{display:grid;grid-template-columns:1.02fr .98fr;gap:70px;align-items:center}.eyebrow{color:var(--blue);font-size:14px;font-weight:800;letter-spacing:.08em}.hero h1{margin:22px 0;font-size:clamp(46px,6vw,72px);line-height:1.08;letter-spacing:-.055em}.hero p,.section-head p{margin:0;color:var(--muted);font-size:17px;line-height:1.85}.hero-actions{display:flex;gap:12px;margin-top:30px}.hero-card{padding:34px;border:1px solid var(--line);border-radius:26px;background:rgba(255,255,255,.84);box-shadow:var(--shadow)}.hero-card-label{color:var(--blue);font-size:12px;font-weight:800}.hero-card h2{margin:15px 0 18px;font-size:26px}.hero-list{display:grid;gap:12px;margin:0;padding:0;list-style:none}.hero-list li{padding:14px 16px;border-radius:12px;color:#4f5664;background:var(--soft);font-size:14px}.hero-list li:before{content:"✓";margin-right:9px;color:var(--green);font-weight:900}section{padding:96px 0}.section-head{max-width:720px;margin-bottom:44px}.section-head h2{margin:15px 0;font-size:clamp(34px,4.2vw,50px);line-height:1.18;letter-spacing:-.04em}.grid-3{display:grid;grid-template-columns:repeat(3,1fr);gap:17px}.card{padding:28px;border:1px solid var(--line);border-radius:20px;background:#fff}.card .num{color:var(--blue);font-size:13px;font-weight:900}.card h3{margin:16px 0 10px;font-size:20px}.card p{margin:0;color:var(--muted);font-size:14px;line-height:1.75}.dark{color:#fff;background:#11131a}.dark .section-head p{color:#9ca3b3}.case-box{display:grid;grid-template-columns:.9fr 1.1fr;gap:44px;padding:42px;border:1px solid #2b2e39;border-radius:26px;background:linear-gradient(145deg,#1a1d27,#14161d)}.case-box h3{margin:15px 0;font-size:32px}.case-box p{color:#aeb4c2;line-height:1.8}.case-data{display:grid;gap:10px}.case-row{display:flex;justify-content:space-between;padding:16px 18px;border:1px solid #303440;border-radius:13px;color:#bbc1ce;background:#1d202a;font-size:13px}.case-row strong{color:#fff}.case-row span{color:#aebeff;font-weight:800}.process{background:var(--soft)}.process-flow{display:grid;grid-template-columns:repeat(4,1fr);gap:14px}.step{position:relative;padding:26px 22px;border:1px solid var(--line);border-radius:18px;background:#fff}.step b{display:block;margin-bottom:12px;color:var(--blue);font-size:13px}.step h3{margin:0 0 9px;font-size:17px}.step p{margin:0;color:var(--muted);font-size:13px;line-height:1.65}.cta{padding:50px 0 88px}.cta-panel{display:grid;grid-template-columns:1fr 225px;gap:50px;align-items:center;padding:58px 64px;border-radius:28px;color:#fff;background:linear-gradient(120deg,#2449df,#653ee8 60%,#902ec9)}.cta h2{margin:0 0 14px;font-size:38px;letter-spacing:-.035em}.cta p{margin:0;color:rgba(255,255,255,.78);line-height:1.8}.qr{padding:12px 12px 15px;border-radius:18px;color:#222;background:#fff;text-align:center}.qr img{display:block;width:100%;border-radius:9px}.qr b{display:block;margin-top:10px;font-size:13px}.qr span{display:block;margin-top:4px;color:#858a97;font-size:10px}footer{padding:34px 0;border-top:1px solid var(--line);color:#858b98;font-size:12px}.footer{display:flex;align-items:center;justify-content:space-between}.case-list{display:grid;gap:18px}.case-item{display:grid;grid-template-columns:180px 1fr 200px;gap:30px;align-items:center;padding:28px;border:1px solid var(--line);border-radius:20px;background:#fff}.case-tag{display:inline-flex;align-items:center;justify-content:center;min-height:90px;border-radius:16px;color:var(--blue);background:#edf1ff;font-weight:800}.case-item h2{margin:0 0 9px;font-size:24px}.case-item p{margin:0;color:var(--muted);font-size:14px;line-height:1.7}.case-result{padding:15px;border-left:2px solid var(--blue);color:#3c4350;background:var(--soft);font-size:13px;line-height:1.7}
@media(max-width:850px){.nav-links{display:none}.hero-grid,.case-box,.cta-panel{grid-template-columns:1fr}.grid-3{grid-template-columns:1fr}.process-flow{grid-template-columns:repeat(2,1fr)}.case-item{grid-template-columns:130px 1fr}.case-result{grid-column:2}.qr{width:225px}.hero{padding:70px 0}.cta-panel{padding:42px 28px}}
@media(max-width:560px){.container{width:calc(100% - 32px)}.nav{gap:10px}.nav-actions a:first-child{display:none}.hero h1{font-size:46px}.hero-actions{flex-direction:column}.process-flow{grid-template-columns:1fr}.case-item{grid-template-columns:1fr}.case-result{grid-column:auto}.case-tag{min-height:70px}.cta h2{font-size:31px}.footer{align-items:flex-start;flex-direction:column;gap:15px}}

/* Shared product navigation: keep identical to the GPT 无限 homepage. */
.nav-shell{position:sticky;z-index:30;top:0;height:72px;border-bottom:1px solid rgba(226,230,239,.8);background:rgba(255,255,255,.88);backdrop-filter:blur(18px)}
.nav{display:flex;height:100%;align-items:center;gap:34px}
.brand{display:flex;align-items:center;gap:11px;margin-right:18px;font-size:19px;font-weight:800;letter-spacing:-.02em;white-space:nowrap}
.brand-mark{display:grid;width:34px;height:34px;place-items:center;border-radius:10px;color:#fff;background:linear-gradient(145deg,var(--blue),var(--violet));box-shadow:0 8px 22px rgba(69,78,244,.25);font-size:13px;letter-spacing:-.08em}
.version-pill{padding:3px 7px;border-radius:999px;color:#667099;background:#eef1f8;font-size:9px;font-weight:800;letter-spacing:.04em}
.nav-links{display:flex;align-items:center;gap:29px;color:inherit;font-size:inherit}
.nav-item,.nav-link{position:relative;border:0;background:transparent;color:#363a45;font-size:15px;cursor:pointer}
.nav-link:hover,.nav-item:hover>button,.nav-item:focus-within>button{color:var(--blue)}
.nav-item>button{display:inline-flex;align-items:center;gap:6px;padding:22px 0;border:0;color:#363a45;background:transparent;font:inherit;cursor:pointer}
.chevron{font-size:11px;transition:transform .2s ease}
.nav-item:hover .chevron,.nav-item:focus-within .chevron,.nav-item.open .chevron{transform:rotate(180deg)}
.dropdown{position:absolute;top:calc(100% - 4px);left:-22px;width:310px;padding:10px;border:1px solid var(--line);border-radius:18px;background:rgba(255,255,255,.98);box-shadow:0 20px 60px rgba(22,30,65,.14);opacity:0;visibility:hidden;transform:translateY(8px);transition:.18s ease}
.nav-item:hover .dropdown,.nav-item:focus-within .dropdown,.nav-item.open .dropdown{opacity:1;visibility:visible;transform:translateY(0)}
.dropdown a{display:grid;grid-template-columns:42px 1fr;gap:11px;align-items:center;padding:12px;border-radius:13px}
.dropdown a:hover{background:#f4f6ff}
.drop-icon{display:grid;width:42px;height:42px;place-items:center;border-radius:12px;color:var(--blue);background:#eaf0ff;font-size:13px;font-weight:800}
.dropdown strong{display:block;margin-bottom:3px;font-size:14px}
.dropdown small{display:block;color:var(--muted);font-size:12px;line-height:1.45}
.nav-actions{display:flex;align-items:center;gap:10px;margin-left:auto}
.login{padding:10px 13px;color:#3f4450;font-size:14px}
.mobile-toggle{display:none;border:0;background:transparent;font-size:25px;cursor:pointer}

@media(max-width:980px){.nav{gap:14px}.nav-links{gap:17px}}
@media(max-width:760px){
  .nav-shell{height:64px}.nav{gap:10px}.brand{margin-right:auto}.version-pill{display:none}
  .nav-links{position:fixed;top:64px;right:0;left:0;display:none;align-items:stretch;flex-direction:column;gap:0;padding:12px 20px 24px;border-bottom:1px solid var(--line);background:#fff;box-shadow:0 18px 35px rgba(31,39,70,.1)}
  .nav-links.open{display:flex}.nav-link,.nav-item>button{display:flex;width:100%;justify-content:space-between;padding:14px 8px;text-align:left}
  .dropdown{position:static;display:none;width:100%;padding:4px;border:0;box-shadow:none;opacity:1;visibility:visible;transform:none}
  .nav-item.open .dropdown{display:block}.nav-item:hover .dropdown:not(:focus-within){display:none}
  .nav-actions .login{display:none}.nav-actions .button{min-height:38px;padding:0 13px}.mobile-toggle{display:block}
}